Effect of Helicobacter pylori eradication on blood ammonia levels in cirrhotic patients: a systematic review.

BACKGROUND/AIMS: The effect of Helicobacter pylori (H. pylori) eradication on blood ammonia levels in cirrhotic patients is still controversial. We aimed to clarify this effect by performing a quantitative meta-analysis of published studies. METHODOLOGY: We searched PubMed, EMBASE and Cochrane library for studies which explored the effect of H. pylori eradication on blood ammonia levels in cirrhotic patients before March 2012. A random-effects meta-analysis was performed. RESULTS: Nine studies (five non-randomized control studies and four before-after studies) involved in 699 cirrhotic patients who were given H. pylori eradication eligible to our analysis. The before-after studies suggested that H. pylori eradication can significantly reduce the blood ammonia levels in cirrhotic patients (SMD=0.32, 95%CI=0.11-0.53, 12=39.6%). After included five non-randomized control studies,the overall results suggested that H. pylori eradication can not reduce the blood ammonia levels in cirrhotic patients (SMD=-0.36, 95% CI=-0.83-0.11) and with significant heterogeneity (1=89.3%). Subgroup analysis suggested that the no effect was found between Caucasian and Asian ethnicity and between cirrhotic patients with Child-Pugh class B/C <70% and >70%. CONCLUSIONS: The effect of eradication of H. pylori on blood ammonia levels in cirrhotic patients is mainly caused by the non-specific effect of antibiotics regardless of patients' ethnicity and impairment of liver function. However, due to limited studies available and low methodological quality that marked by high risks of bias, our study should be interpreted cautiously.